The basic concept involves reinforcing a hard ceramic matrix with extremely strong, stiff silicon carbide crystals, commonly called whiskers. These whiskers are grown under carefully controlled conditions and due to their high purity and lack of grain boundaries approach the theoretical maximum strength obtainable.
   The increase in fracture toughness of the material is such that inserts are now offered without hones as a standard, making them suitable for finish cuts on most forged nickel base alloys without "smearing".
   WG-300 has outstanding thermal and mechanical shock resistance. It can withstand interruptions, provided recommended speeds are increased. Velocity is all important in the successful cutting of parts with interruptions.
   Most of the heat generated during metal cutting is dissipated by the chip carrying it away. As cutting speeds increase, the metal cutting process becomes more adiabatic. In other words, the heat generated in the "shear zone" cannot be conducted away during the very short time in which the metal passes through this zone. Therefore, we can benefit from the heat generation, temperature rise and softening effects in the "shear zone". The heat generated in the "shear zone" has been traditionally thought of as a negative factor since it is also associated with heat related failure of cemented carbide cutting tools. This often leads to the need to slow down the cutting operation to a point where carbide inserts will give acceptable life.
   WG-300 is able to withstand high temperatures while maintaining strength and hardness and it has been shown that contrary to traditional methods of machining, we can, in fact, use the heat generated in the "shear zone" ahead of the tool to our advantage. There is an optimum speed outside the range of carbide tools where the heat generated lessens the cutting forces by softening the metal and aiding in the grain boundary dislocation.
   This advantage can be very dramatic, sometimes moving the possible metal cutting speeds from a few hundred feet per minute to thousands of feet per minute! Such is the case with Greenleaf WG-300 whisker reinforced ceramic when applied to most forged nickel-base alloys. Optimum speeds can be achieved with temperatures exceeding 1000* Celsius.
   The excellent thermal shock resistance of WG-300 results in a cutting material which can be used either dry, wet or even intermittently cooled without fear of catastrophic tool failure from thermal cracking.
   The outstanding hardness of WG-300 inserts, combined with the high strength imparted by the reinforcing silicon carbide whiskers, makes possible the machining of many materials previously workable only by grinding. Heat treated alloy steels, die steels, weld overlays and hard irons with interrupted cuts are just a few of the successful applications of WG-300.
   If your job is in the 45 Rc to 65 Rc range, chances are that Greenleaf WG-300 can increase productivity and cut machining costs substantially.